#define _CRT_SECURE_NO_WARNINGS 1
struct ListNode* FindKthToTail(struct ListNode* pListHead, int k) {
    struct ListNode* right = pListHead;
    struct ListNode* left = pListHead;
    while (k--) {
        if (right == NULL) {
            return NULL;
        }
        right = right->next;
    }
    while (right) {
        left = left->next;
        right = right->next;
    }
    return left;
}